1. Field of the Invention
The present invention relates to a head of an inkjet printer, and more particularly to an improved service station device of a head for inkjet printer, wherein a stroke span of cleaning and capping operations of a head nozzle is minimized for shortening a printing operation time and simplifying the structure, thereby assisting to accomplish minimization of the printer.
2. Description of the Prior Art
An inkjet printer is formed by a carriage which is moved side to side by means of a timing belt under a guidance of a timing pulley installed onto a main frame, and a head which is mounted to the carriage for ejecting ink while being moved together with the carriage. Also, a nozzle installed to the head for issuing the ejected ink to have a prescribed pattern, and a service station part for wiping out or closing off the head in accordance with a cleaning signal at constant intervals during performing the printing are provided.
The service station part includes, as shown in FIG. 1, a forward/backward driving motor 650 fixedly installed to the outer side of a driving main body 640 to be driven, and a worm gear 660 fixedly installed to forward/backward driving motor 650 in a body to be rotated forward/backward by the driving force. In addition to these, a screw shaft 670 is rotated by being perpendicularly erected with respect to driving main body 640, and a worm wheel 680 integrally formed to the lower end of screw shaft 670 receives the driving force of worm 660 for forward/backward rotating screw shaft 670. A vertical operation unit 690 is screw-coupled to screw shaft 670 to ascend/descend in accordance with the rotating direction of screw shaft 670, and a see-saw stand 700 installed to a case 630 by means of a shaft pin 701 to be rotatable has one end connected to the free end of vertical operation unit 690 for performing the see-saw motion at both ends thereof. A wiper 611 and a cap 621 are respectively fixed to both upper ends of see-saw stand 700 for cleaning or closing nozzle 41 of head 40.
Since the printing operation is carried out by ejecting the ink via nozzle 41 (having a caliber of 5/100 mm) of head 40, the service station part functions for cleaning out nozzle 41 of head 40 and closing nozzle 41 before/after performing the printing to inhibit the ink from being hardened at nozzle 41 when the printing is not performed.
FIG. 2A shows a neutral state during the printing, in which wiper 611 and cap 621 commonly maintain the level with each other.
FIG. 2B shows an operating procedure when cleaning nozzle 41, in which, after the carriage mounted with head 40 performs the printing operation via nozzle 41 of head 40 while being moved side to side, forward/backward driving motor 650 is driven forward in accordance with a signal when the carriage is moved to a service area to be adjacent to the service station part for preparing the succeeding printing operation. Then, the resulting driving force rotates screw shaft 670 via worm 660 and worm wheel 680, and screw-coupled vertical operation unit 690 is moved downward along the spiral direction by the rotation of screw shaft 670. Along with the descending operation of vertical operation unit 690, see-saw stand 700 connected thereto performs the see-saw motion centering about shaft pin 701 to ascend wiper 611 and to descend cap 621. Therefore, nozzle 41 of head 40 is cleaned by ascending wiper 611.
FIG. 2C shows an operating procedure of closing nozzle 41, in which nozzle 41 cleaned by wiper 611 is continuously moved toward cap 621. Then, forward/backward driving motor 650 is driven by a signal in the direction reverse to the above-described operation, and the resulting driving force rotates screw shaft 670 in the direction reverse to the above-described operation via worm 660 and worm wheel 680. By the reverse rotating motion of screw shaft 670, screw-coupled vertical operation unit 690 is moved upward along the spiral direction. Then, the ascension of vertical operation unit 690 induces the see-saw motion of see-saw stand 700 connected thereto by centering about shaft pin 701, so that wiper 611 descends and cap 621 ascends. Therefore, nozzle 41 of head 40 is covered by ascending cap 621 to be closed.
However, the foregoing service station part has the following problems.
First, the driving part for driving to operate wiper 611 and cap 621 such as driving main body 640, forward/backward driving motor 650, worm 660, worm wheel 680, screw shaft 670, vertical operation unit 690 is required to complicate the structure. Consequently, the assembling process is added to degrade production efficiency and to increase cost. Furthermore, such a driving part requires a relatively wider installation space within the printer to enlarge the dimensions of the printer.
Second, the carriage is stopped so as to operate wiper 611 and cap 621, respectively. Therefore, the stroke time of the driving part is lengthened to slow down the cleaning and closing operation times.